The overall objective of this proposal is to establish a Clinical Research Consortium to define the outcomes of ALDLT. We propose the following specific aims to fully evaluate the impact of ALDLT: 1. Core Study: Establish a Donor and Recipient Core Information Database for Adult LDLT and Non-ALDLT Patients Hypothesis: ALDLT short-term survival outcomes, but not complication rates, are equivalent to whole cadaveric and SLT transplantation. We and others, achieved excellent short-tem survival outcomes of ALDLT, despite a high rate of recipient complications, in non-urgent patients. To fully evaluate the benefits of ALDLT, the technique will be applied to both urgent and non-urgent recipients, and compare its outcomes to three sets of patient cohorts that include: a) whole organ recipients, b) cadaveric SLT recipients, and c) candidates who ultimately do not receive a transplant. The living donor section will compare living donors and potential donors who do not undergo donation. Primary endpoints define survival outcomes and complication rates in donors and recipients at 1, 2 and 3 years posttransplantation. This will elucidate the efficacy of ALDLT as compared to whole cadaveric, SLT, and control (untransplanted) patients in the entire spectrum of recipients'status, and determine if ALDLT is justified when compared to the natural history of non-transplanted non-urgent controls. Secondary endpoints assess the impact of technical variations on postoperative recovery, liver regeneration postdonation, impact of living donation on the cadaveric donor pool, and defines donor exclusion criteria.2. Clinical Research Protocol for Recipient Outcome: Determine the impact of ALDLT on Posttransplant HCV Recurrence in Transplant Recipients Hypothesis: ALDLT may be accompanied by accelerated recurrence of HCV versus whole cadaveric liver transplantation. Rapid and severe HCV recurrence observed, at our center, in ALDLT recipients compared to whole organ transplant patients, may offset the benefits of early transplantation with living donors. This protocol compares the time to histological recurrence of HCV in ALDLT and whole organ graft recipients at 6 months, 1, 2, and 3 years posttransplantation. The effects on patient and graft survival and the correlation between the degree of histological disease and HCV RNA levels are investigated by our secondary endpoints.3. Clinical Research Protocol for Donor Outcome: Determine Health-Related Quality of Life Outcomes and Resource Utilization of Adult Living Donation Hypothesis: HRQL of living donors is impacted in the short-, but not, the long-term and the HRQL of ALDLT recipients may be enhanced following ALDLT. HRQL in both donors and recipients will be compared before ALDLT and at 6 and 12 months posttransplantation through generic and disease-specific instruments. Additionally, health utility index assessments and evaluation of health care resource utilization will be conducted.